In cold regions, the structural tubular elements, no matter the shape that they exhibit, i.e. rectangular, square or circular, are often subjected to atmospheric ice precipitations, like hard frost, black ice and wet snow. The ice accumulation on these elements may cause mechanical overloads that will deform them, even going so far as to sometimes produce disastrous mechanical breakages. So far, there are no methods truly efficient from the energetic and automatized point of view, that are capable of reducing the ice accumulation on these structural elements.
The U.S. Pat. No. 4,690,353 (HASLIM) and the U.S. Pat. No. 5,411,121 (LAFORTE et al.) describe devices or systems using high intensity electromagnetic impulses to break the ice.
In the case of HASLIM, the system is applicable to planar surfaces, and has been developed to remove the ice on the wing of an airplane. Electromagnetic pulses are injected in a thin double ribbon of copper positioned (embedded) in a rubber film.
In the case of LAFORTE et al., the device is applicable to stranded conductors, like a stranded cable. To break the ice, electromagnetic impulses are injected in some of the insulated, integrated conductive wires in the last stranded layer of the cable. These conductive wires are insulated for this purpose during the manufacturing process of the cable.
The publication entitled "An Investigation of Power Line De-icing by Electro-Impulse Methods", published in the paper IEEE Transaction on Power Delivery, Vol. 4, No. 3, July 1989 in the name of EGBERT et al., describes a test with an ACSR conductor coated with rubber bands containing flexible copper strips in which electromagnetic impulses have been injected. In this test, the rubber bands surrounding the conductor had not an appropriate shape and the copper strips, too thin, were not providing a sufficient mechanical resistance to break the ice, so that under the effect of impulses, the coating was deforming instead of breaking the ice, the mechanical resistance of the copper strips being lower than that of the ice. As underlined by the authors as a conclusion of their experimentation, the use of this type of overlapping does not allow to efficiently de-ice the closed surface of a conductor.